The objectives of this core are the following. 1. Provide statistical and epidemiologic support to ongoing or planned obesity studies in the Boston area, which will, in turn, expand the nucleus of expertise and familiarity with design and analysis issues unique to obesity research. 2. Continue to support the development and maintenance of data sets amendable to secondary epidemiologic analyses regarding obesity and nutrition issues as well as to develop and refine measures of obesity. 3. Interface epidemiology, basic sciences, and clinical medicine so that hypotheses generated by these areas can be tested in ongoing epidemiologic studies. 4. Train young investigators in epidemiologic and statistical techniques used for the study of obesity in populations. 5. Disseminate methods/approaches to data analysis to a broad audience, as Core members gain experience in applying and refining quantitative methods. 6. Help identify groups at high and low risk of the development of obesity, and population characteristics for obesity clinical trials.